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(11) | EP 1 081 834 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Methods of operating step-up DC voltage converters and step-up DC voltage converters |
| (57) The invention relates to methods of operating step-up DC voltage converters including
a storage choke, the one terminal of which is connected to the input of the converter
and the other terminal of which is connectable via a first controllable switch to
ground and via a second controllable switch to the output of the converter; a clock
outputting a first clock signal dictating the switching cycle of the converter, and
a second clock signal, the cycle of which corresponds to that of the first clock signal;
and a regulator circuit which regulates the voltage at the output of the converter
to a setpoint value. In the methods the second switch is set ON at the end of the
switching cycle during a constant time duration as dictated by the second clock signal
and which as compared to the length of the switching cycles is short, whilst the first
switch is set OFF, so that a transient flow of energy occurs from the output of the
converter to the input of the converter. Due to this, the converter is always operable
at a constant frequency independent of the load and thus permits simple noise filtering
of the output voltage which is particularly of advantage in telecommunication applications.
The invention relates furthermore to step-up DC voltage converters for implementing
the method. |